The Catholic Church and Politics

In recent times the Catholic Church has made a manifest effort to get as far away from politics as possible. The last few Popes have publicly stated that the Church advocates no political positions and have condemned priests or bishops who engage in any sort of political lobbying. In Poland priests or other Church officials who endorse politicians are severely criticized and treated as if they are people who do something wrong. But to me, this seems pretty shallow. The separation of Church and State does not imply that people involved in the Church cannot have any say in the State, nor does it mean that people who work for the State can't be members of the Church. Back in Communist days, this was indeed the case. If someone went to Church or declared themselves a Catholic, there was no way he (or she) would ever be allowed to work for the State. The separation of Church and State simply means that Church officials have no political administrative power and are not State officials (and vice versa - State officials are not Church officials). In England, for example, the Queen is both head of State and head of the Church of England. And nobody seems to have a problem with it, since the Queen no longer has any political power anyway...
But let's get back to the Catholic question: why can't the Church advise its followers (who are members of the Church) on how they should vote? For example, I think it is admirable when Church officials praise pro-life candidates and denounce pro-death candidates on the abortion question. I see nothing wrong with the Church endorsing such candidates ('pro-lifers')! In fact, I think it's very strange that the Church takes no position on political issues directly. I also think it is shameful for any Catholic to vote against the Church commandments. In the United States, for example, most Catholics vote for Democrats - why, I will never know...
I also don't know why the Church shouldn't be allowed to mandate its members to vote for someone or other. It's all purely voluntary! Labour unions regularly endorse candidates, and many labour unions are compulsory bodies. Now that is real vote extortion! Why do labour unions have more power and privilege than Churches do?
I recognize, of course, that even Catholicism itself is rather 'shaky' when someone tries to approach it systematically. For instance, St. Thomas Aquinas, who was probably the greatest Catholic theologian, believed that the soul only enters the foetus 6 weeks into the pregnancy for boys, and 8 weeks for girls. Clearly this would mean that abortion up to that time is allowed. There are also many other strains of Catholicism. I attend an Augustinian University and it is visibly very different traditionally from the Catholicism I was raised in as a child.

St. Thomas Aquinas was one of the greatest Catholic theologians and one of the most important philosophers in Western thought. He brought Aristotle back into the Western world. He recreated the logic of that great Greek - he dispelled the accursed Platonic mist which held down all Western philosophy. And it was he who said that "reason in man is rather like God in the world". That's right, REASON is our primary guide in this world. We have nothing else to support us, or back us.